The complete set comprises:

• 4-part black anodised aluminium case, 122 x 45 x 160mm deep, including 8 screws
• 2x toggle switch
• 2x push button, RED colour
• 4x self-adhesive cabinet feet
• 4x 6mm nylon hex spacer for mounting U3 to front panel
• 4x black metal M3 screw for mounting U3 to front panel
• BNC socket
• Power socket
• Matching power plug
• 9-way D-connector (to be used for GPS, programming, whatever you want)

Click the following photos to open the larger versions:

There is plenty of space in the box for more stuff to be added (voltage regulators, amplifiers, more modules, who knows!). The photos show a U3 with relay-switched LPF board and full complement of LPF modules plugged in.

The right toggle switch is labeled "Power", for switching the unit On and Off. I purposely left out an "On" and "Off" label because different parts of the world disagree on whether On should be down or up, e.g. US has "On" conventionally up, whereas UK has "On" conventionally down. When wiring the power switch, simply use two of the switch terminals, i.e. use the switch in single-throw (SPST) mode; for example, wire the switch between the incoming +5V lead from the power socket, and the +5V pad on the U3S board edge.

The left toggle switch can be used for whatever else you want. You could use it to select power level, switch the LCD backlight off, or any other thing which takes your fancy.

Construction is straightforward and you can customise it to your need. Remove the M3 nylon screws that bolts the LCD module to the main U3 board and instead screw in the four 6mm hex spacers. Then just bolt the U3 assembly behind the front panel using the four supplied black screws. When you need to access part of the U3 in the box, it is easy because you can remove the top and bottom halves independently.

Important note! The top and the bottom half of the box are identical pieces. On one side, they have a U-groove. On the other side, an I-tongue. The top and bottom halfs must therefore be orientated correctly so that the U of the bottom fits the I of the top, and vice versa on the other side. If it seems that your front/rear panels don't fit properly onto the box, then probably you have forgotten that you have to turn around one half of the box, so the U and I fit into each other!

The flats of the transistors are a few mm away from the lower half of the aluminium box. With some ingenuity there would be an opportunity here to fix the transistors against the lower aluminium so that it behaves as a large heatsink.

I strongly recommend:

1) inserting all screws loosely, and only tightening them up when they are all aligned in place.

2) Do not over-tighten any screws, particularly the black metal mounting screws that are screwed into the nylon spacer. Over-tightening them would deform the nylon and the screw thread would lose grip.

3) When fitting front panel controls be careful not to scratch the metal surface with pliers etc! I found that they can be tightened sufficiently by hand, as the nuts grip the panel. No pliers were needed, for the front panel controls. You will need pliers for the rear panel connectors.